Bowling activity indicator



June 13, 1967 E. s. SEELEY 3,325,801

BOWLING ACTIVITY INDICATOR Filed Dec. 26, 1963 EDWARD S. SEELEY United States Patent O 3,325,801 BOWEN@ ACTIVITY INDICATGR Edward S. Seeley, 387 Race Track Road, Ho Ho Kus, NJ. 07423 Filed Dec. 26, 1963, Ser. No. 334,683 9 Claims. (Cl. Mtl-323) This invention relates to the control of bowling centers equipped with mechanical pinsetters and, more particularly, to indicators for aiding the operators of such centers to so control operations as to secure maximum utilization of the facilities. It is important to the protability of a bowling enterprise to minimize slow play by bowlers, particularly during the periods when all the lanes are in play. Some examples of loss of paid time are as follows: after a lane is assigned, the customer may be very dilatory in commencing to begin bowling; due to social distraction or other cause, bowlers may fail to play at a reasonable minimum rate; after a customer has finished play, an excessive period often passes before he notifies the attendant that the lane can be reassigned, during which time the lane is idle; in some cases the customer dishonestly leaves the building without paying for his play, the attendant not being aware that play has been completed at that lane. Furthermore, when there is no waiting customer, it is important to economical operation that the power to the pinsetter of the lane where play is completed be turned off promptly.

It is an object of the present invention to provide an attention-commanding signal at the control desk which will inform the desk operator when a customer is too slow to start play after being assigned a lane.

Another object of the invention is to provide a signal to inform the desk operator when play is unduly slow.

A third object is to provide a signal to notify the operator when play has been completed in order that the lane can be promptly reassigned, and to alert the operator to the possibility of failure to pay for play.

A brief outline of the operation of an automatic pinsetting machine will facilitate a complete understanding of the invention. The bowling center constists of a number of lanes down one of which an individual player rolls a ball with the object of upsetting as many as possible of the ten pins standing at the end of the lane opposite the player. If the iirst ball does not upset all of the pins, the pinsetting machine goes through a partial operation in which the fallen pins remaining on the lane are removed but are not reset. lf all pins are knocked over by the rst ball, or after the second ball has been thrown, the machine goes through a complete operation in which all pins are rst removed from the lane and then all ten pins are reset in their normal starting positions. The machine thereupon momentarily closes a circuit which causes an electro magnetic counter located at the control desk to register the operation, the count representing the total amount of play and serving as a basis for charging the player for the use of the lane. When the lane is not in use, power to the pinsetter for that lane is turned olf at the control desk, and turned on again when a new player is assigned to that lane.

In one embodiment of the invention, a signal lamp is made to function as follows: so long as a lanecontrol switch at the control desk is in the OFF position, a signal lamp associated with that lane switch will be dark; when the lane is assigned to a new player and the switch is thrown to the ON position, the lamp lights and burns steadily; after, typically, five minutes, if play has not already proceeded to the point where the iirst complete operation of the machine takes place, the lamp will ash intermittently, signifying that play is too slow; after play commences the light will burn steadily again until the time between successive complete operations of the ice machine exceeds, typically, 60 seconds, when the lamp again flashes intermittently to signify slow play and allow the manager to inform the players to increase their rate of play; at the conclusion of play, 60 seconds after the machine resets with complete operation, the flashing lamp informs the attendant that the play has terminated, which he confirms by glancing at the lane, whereupon the lane should be immediately reassigned, or turned oil to conserve power and mechanical wear. It is commonplace for a machine to malfunction and require the service of maintenance personnel who shut the machine down by means of a switch located at the Inachine. In accordance with this invention the lamp flashes during the time that the machine is turned olf by this switch, thus reminding the operator that this lane may not be lassigned until the lamp is again dark or burns steadily. The maintenance condition is recognized by the flashing of the signal lamp coupled with the loss of illumination over the pin area of the lane. Failure of a circuit breaker, Whether or not the lane is in play, will also result in the lamp flashing after a time passage of up to 60 seconds. The two periods of time, namely 5 minutes and 60 seconds, are cited merely for example and to clarify the description and are not unique or limiting to the invention. g

All of the actionsAv of the lamp as described in the foregoing provide intelligence to the control operator to enable him to manage the bowling facilities eiciently and economically. Since the control operator has numerous duties to carry out in connection with the 24 to 48 or more lanes under his control and supervision, the flashing light with its generalized message that money is being lost on that lane is a most important aid. Since the invention is a means of controlling the lamp to operate in the unique manner described, its value will be clearly recognized.

The following description of the invention should be read in connection with the accompanying drawings, in which:

FIGURE l is a circuit diagram of a preferred embodiment of the invention.

FIGURE .2, FIGURE 3 and FIGURE 4 are diagrams representing time variations of voltage that are vnecessary for an understanding of the operation of FIGURE 1.

FIGURE l is a circuit diagram of an embodiment of the invention, showing its inclusion in a pinsetting equipment of common type. The pinsetting equipment will include a source of voltage lt), which causes relay 12 to operate upon closing of switch ld located at the control desk, where all pinsetters are remotely controlled by an attendant. Operation of relay l2 causes contacts le to close and connect .power to the pinsetting machine which is thereby turned on. Each time the pinsetting machine sets up the full complement of pins, switch 18 is automatically closed momentarily, causing voltage to be applied to the electromagnetic counter 20, located at the control desk, which becomes energized, advancing the counting drums to the next higher number. Items l0, 12, 14, 16, 18 and 26 are commonly parts of the pinsetting equipment and its control.

ln accordance with this invention, the voltage applied to the counter is rectified by diode 22 and smoothed by capacitor 24.

The indicated polarity of diode 22 is necessitated by the fact that at least one pinsetter in common use supplies direct voltage to the counter, the positive side being to diode 22. The voltage, being of short duration, constitutes a pulse, positive in polarity, which is converted to a negative pulse by phase inverter 26, and transmitted through diode 28 to charge capacitor 30 and bias the grid of tube 32 well beyond cutoff. The duration of the pulse is usually not more than a few seconds. The

. La charge is then slowly removed from capacitor 30 by resistor 34 while diodes 23 and 36 prevent the capacitor from discharging into other parts of the circuit. Capacitor 30 will discharge sufliciently to permit plate-cathode current to flow in tube 32 in, typically, 60 seconds. It will be shown later that when this current ows, lamp 38 will light intermittently provided switch 14 is closed.

When switch 14 is open, the voltage from source 10 is rectied by diode 40 and smoothed by capacitor 42. It will be shown later that when this voltage exists across capacitor 42 lamp 38 is dark.

When switch 14 was rst opened, capacitor 42 became charged; and as terminal 46B of capacitor 46 rose to a positive potential, current owed out of terminal 46A through diode 48 in the forward direction to the circuit return conductor 50, charging capacitor 46. Capacitor 30 likewise charged through diodes 36 and 48. When switch 14 is subsequently opened, resistor 44 rapidly drains the charge from capacitor 42 and the potential of terminals 30B and 46B drops to that of the return conductor Si), while the potential of terminals 30A and 46A drop to a negative value numerically equal to the previous positive potential of terminals 30B and 46B. Diode 48 now blocks current ow to conductor 50, while both capacitors have free flow of current to resistor 34, the voltage driv- I ing the grid of vacuum tube 32 to cutoff as previously described. By making capacitor 46 much larger than capacitor 30,v the time required for discharge through resistor 34 may be made, typically, 5 minutes in contrast to the 60 second period mentioned above as a typical value after switch 18 is opened.

It has been stated in the foregoing description of the circuit that the action of lamp 38 depends upon the i'low of plate-cathode current in tube 32 and on the existence or absence of voltage across capacitor 42. It will now be shown how these circuit conditions produce three conditions of the lamp-dark, steady light, and flashing light to dark. Oscillator 52 produces a voltage which switches between a large negative value and a small negative value in the manner depicted in FIGURE 2. This oscillator is connected to the junction point S4 by resistor 56. Similarly, resistor 58 connects the junction point 54 to capacitor 42 and resistor 60 connects the junction to the cathode of tube 32. Junction 54 is connnected to the base of P-N-P transistor 62, the collector of which is connected to the negative terminal of a source of a D-C potential 64 through lamp 38 and the emitter of which is connected to the positive terminal of the D-C source 64 and return conductor 50. The property of the circuit consisting of the transistor, lamp and source of potential is such that a current Hows through the lamp and the lamp lights when a negative potential of adequate magnitude is connected to the base of the transistor, and current is eifectively stopped and the lamp is dark when the base is at a positive potential with respect to the emitter of the transistor. To consider the voltage applied to the base through resistors 56, 5S and 6@ it is convenient to assume rst that the connection between junction point -54 and the base of transistor 62 is omitted. The graph of FIGURE 2 depicts the voltage supplied by oscillator 52; it also qualitatively represents the voltage at junction 54 when the grid of tube 32 is strongly negative so that cathode current does not flow and when no current is supplied to capacitor 42 through diode 4t) due to switch 14 being in the closed condition. The voltages indicated in FIGURE 2 are su'lciently negative at all times that when point 54 is connected to the base of the transistor sufficient current flows into the base on either phase of the voltage wave to drive the collector current to saturation so that current of maximum magnitude continuously ows through the lamp which therefore burns steadily. Again with switch 14 closed but with the grid of tube 32 at a zero potential or a small negative potential so that plate-to-cathode current canflow, then the voltages shown in FIGURE 2 are shifted in the positive direction and the potential of point 54 will change cyclically from positive to negative to positive, etc., as depicted in FIG- URE 3. If point 54 is now connected to the base of transistor 62 as shown in FIGURE 1, the current through the lamp will alternate from full value to essentially zero, causing the lamp to flash. As a third alternative, if switch 14 is open, the voltage across capacitor 42 due to source of A-C voltage 10 will be sucient, in accordance with this invention, to maintain the potential of point 54 positive as depicted in FIGURE 3, and collector current will be cut off and the lamp will be continuously dark.

It will be obvious to one skilled in the art that certain types of solid-state devices may be substituted for tube 32 without changing the operation of the circuit. An example lot' such device is an N-PN transistor of a type having very low input current.

By the novel means described, when the pinsetting ma- Chine is in turned-olf condition by switch 14 being open, the varying negative voltage from oscillator 52 is exceeded by a positive voltage to hold transistor 62 in a cut-olf condition and lamp 38 dark. When switch 14 is operated to the closed condition, the positive voltage is removed and tube 32 is temporarily prevented from passing current by reason of the charge on capacitors 30 and 46 which maintains the lgrid strongly negative, with the result that the transistor base receives only negative voltages of suicien't magnitude to maintain the collector current in saturation, and the lamp burns steadily. After several minutes, according to circuit constants selected, the charge on capacitors 30 and 46 leaks off, allowing cathode current to How and produce a positive voltage atthe cathode of tube 32.which partially opposes the varying negative voltage from oscillator 52 with the result that the potential at the base of the transistor switches alternately positive and negative, the lamp thus being turned oif and on correspondingly. AS a third control of the action of the lamp, when a pulse of voltage is transmitted to the counter on each complete operation of the pinsetting machine, capacitor 30, only, becomes charged thus cutting oil the flow of current in tube 32 and allowing the base `of the transistor to remain continuously negative, the lamp thereby being maintained bright; then after a period selected by the use of appropriate circuit constants the charge is dissipated and the lamp returns to its ashing operation. Y

This invention includes control for establishing the period before ashing of the lamp begins following the termination of the pulse of voltage transmitted on the full operation of the pinsetting machine by selection of the value of capacitor 30 and resistor 34. It .provides control of the period before flashing begins following the closing of switch 14 by selection of capacitor 46 in relation to capacitor 30 and resistor 34.

The periods just referred to are controlled by the product of capacitance and resistance. In order that leakage resistance of diodes 28 and 48 and other possible leakage paths will not significantly affect the time constants, it is desireable to employ a relatively low value for resistor 34 and large values for capacitors 30 and 46. Large values of capacitance are most economically available in electrolytic capacitors. However, the leakage current of electrolytic capacitors may rise to values strongly affecting the time constants if the forming D-C voltage is removed for substantial periods of time. It is a feature of this invention that during the entire period that the pinsetting machine is turned off voltage is applied to maintain polarization of the timing capacitors 30 and 46, so that stability of characteristics over a period of years may be expected if capacitors of high quality are employed.

In the foregoing description details 10, 12, 14, 16, 18 and 20 of FIGURE 1, identiiied as parts of a pinsetter in common use, represent only those portions of the machine that are necessary for an understanding of the description of the invention. Other pinsetters may not in` clude these details in the same form or the same interconnection, but the essential functions upon which this invention depends are provided by all pinsetting machines in general use; namely, a voltage existing across the open contacts of the control switch, and a pulse of voltage transmitted to the electromagnetic counter on each co-mplete operation of the pinsetting machine. In some cases the source of voltage provides a direct voltage to switch 14 having positive polarity so that current iiows readily through diode when the latter is poled as shown in FIGURE l. In this case diode 40 serves no useful purpose, but it is included for universality of application. The method by which this positive voltage charges capacitors 3,0 and 46 to a negative voltage at the grid of tube 32 is described in the foregoing paragraphs. The pulse transmitted to the electromagnetic counter by one or more pinsetting machines is positive direct voltage requiring that diode 22 be poled as indicated in FGURE l and requiring phase inverter 26 to provide negative current to charge capacitor 30.

There has been described and shown hereinabove a novel, useful and practical system for indicating slow play or other loss of time in using the facilities of the bowling center.

I claim:

1. Apparatus to control a signal device in response to presence lor absence of voltage at a rst input and pulses of voltage applied to a second input, comprising a first capacitor connected between the first input land the control terminal of a first current-controlling device hava ing, in addition to the said cont-rol terminal, at least a second and a third terminal, said controlling device being such that when a source of direct voltage is applied between its second and third terminals in appropriate polarity current flows between them if the potential of the control terminal is within a first range of values while current fiow is effectively prevented if the potential of the control terminal is within a second range of values, the current flow thru the control terminal being of low value in relation to the controlled current, a first resistor for establishing a time constant with said first capacitor and connected across said capacitor, a first rectifier having two terminals the first of -which being connected to said control terminal and being of such polarity that the rectifier conducts current readily in the direction required to change the potential of said control terminal from the first to the second said range of values, a second capactor connected between the second terminal of said first rectifier and said first input, a second lrectifier whose first terminal is connected to the second terminal of said first rectifier said first terminal being of the same polarity as the first terminal of said first rectifier, and whose second terminal is connected to the common return side of both inputs, a third rectifier having the same polarity as the first rectifier and -whose first terminal is connected to the first termnial of the first rectifier and whose second terminal is connected to the said second input, a first source of direct voltage connected between the second terminal of said first current control device and the common return side of both inputs and having a polarity corresponding to the polarity of the current control device, a second resistor connected between said first input and the control terminal of a second current-controlling device having also at least a second and third terminal said second controlling device having the properties that when a source of direct voltage is applied between its second and third terminals in appropriate polarity current ows between them if the potential of the control terminal is Within a third range of values while current fiow is effectively prevented if the potential of the control terminal is within a fourth range of values, the current thru the control terminal being low in 'relation to the controlled current, a third resistor connected between the third terminal of the first current-controlling device and the control terminal of the second current-controlling device, a fourth resistor connected between said control terminal of the second controlling device and a source of oscillating voltage which varies cyclically Vbetween a large and a small voltage the polarity of said large voltage being such as would if `acting alone cause current to flow readily thru the second control device, a connection between said signal device and the second terminal of said second control device, a second source of direct voltage connected between said signal ldevice and the common return side of the first and second inputs and having a polarity corresponding to the polarity of the second control device, a connection between the third terminal of said second control device and the common return of the first and second inputs, the voltages provided by said source of oscillating voltage and by the said first and second sources of direct voltage and the values of said second, third and fourth resistors being such that: first, when a voltage having a suiiicient magnitude and the polarity of the said first range of values is applied to the first input, the potential of the control terminal of said second current-controlled device will be within the said fourth range of values for all values of voltage received from said source of oscillating voltage and essentially no current `will iiow thru the signal device; and, second, when with no potential applied to either input the electric charge of the said first capacitor is such as to apply a potential to the control terminal of the said first current-control device that is Within the said .second range of values, essentially no current will fio-w through said third resistor and the potential of the control terminal of the second current-control device will be continuously within the third range of values and current will flow continuously to the signal device; and, third, when the capacitors are sufficiently discharged that the potential of the control terminal of the first control device is within the first range of values, current flows and the potential of the control terminal of the second control device is maintained ywithin the third range of values at moments when the source of oscillating voltage is supplying large values of voltage and within the fourth range of values when the oscillating voltage is in the small voltage phase, current thru the signal device then being alternately caused to flow and cut off.

2. Apparatus as in claim 1 with a fourth rectifier connected between the first `and second capacitors and the first input, its first terminal being connected to the first input and being of the same polarity as the first terminal of the first rectifier.

3. Apparatus as in claim 1 in which the first and second current-control devices are selected from the group consisting of the vacuum tube and the solid state devices.

4. Apparatus to control a signal device in response to the presence or absence of voltage at a first input and pulses of voltage applied to a second input, comprising a first capacitor connected between the control grid of a vacuum tube and the first input, a first resistor for establishing a time constant with said first capacitor and connected across said capacitor, a first rectifier having its anode connected to said grid, a second capacitor connected between the cathode of said first rectifier and said first input, a second rectifier having its anode connected to said second capacitor and first rectifier and its cathode connected to the return side of both said inputs, a third rectifier having its anode connected to said grid and its cathode connected to said second input, a second resistor connected between said first input and the control electrode of a transistor of such type and circuit arrangement in relation to a source of direct voltage that when the control elect-rode is at a negative potential current diows readily through other electrodes of the transistor and said source of direct voltage whereas when the control electrode is at a positive potential substantially no current fiows through the other electrodes, a third -resistor connected between the cathode of said vacuum tube and said control electrode, a fourth resistor connected between said control electrode and a source which supplies a negative voltage which varies cyclically between a large and a small negative value, a connection between said signal device and a second lelectrode of said transistor, said source of direct voltage being connected between said signal device and the return side of both inputs, and a connection between a third electrode of said transistor and return side of both inputs, the voltages provided byV said source of negative voltage and the values of said second, third and fourth resistors being such that: first, when a positive voltage is supplied to said first input said transistor will be biased `to a cut-off condition and pass essentially no current to the signal device; and, second, when said rst or said rst and second capacitors are charged so as to apply negative voltage to said control grid sufficient to bias said tube so that essentially no current ows to the cathode, the transistor will be biased negative so that suicient current will flow continuously through the transistor and the signal device to cause said signal device to operate continuously; and, third, when the said capacitors are sufficiently discharged that current iiows to the cathode of said tube, the potential of said control electrode of ysaid transistor will vary cyclically from positive to negative, causing current to ow intermittently to the signal device and causing said signal device to operate and to be non-operated cyclically.

5. Apparatus as in claim 4 with a fourth rectier having its anode connected to the said rst input and its cathode connected to said irst and second capacitors.

6. `Apparatus as in claim 4 With a phase inverter connected between said second input and said third rectiiier and having the property of delivering a negative pulse at its output upon receiving a positive pulse from the said second input.

7. Apparatus as in claim 6 with a fth rectifier, having its anode connected to the said second input and its cathode connected to the said phase inverter.

8. Apparatus as in claim 6 in which the transistor is of the p-n-p type with the base as the control electrode, the signal device being connected between the collector and the source of voltage and the emitter being connected to the return side of both inputs and the opposite pole of the source of voltage.

9. Apparatus as in claim 8 in which the signal device is a signal lamp.

References Cited UNITED STATES PATENTS 2,589,465 3/ 1952 Weiner 340-248 2,970,303 1/ 1961 Williams 340-248 3,166,318 1/1965 Barger 273-54 3,172,663 3/1965 Goldstien 273-54 3,246,310 4/ 1966 Keller 1 340-223 NEIL C. READ, Primary Examiner.

R. M. GOLDMAN, I. J. LEVIN, Assistant Examiners. 

1.APPARATUS TO CONTROL A SIGNAL DEVICE IN RESPONSE TO PRESENCE OR ABSENCE OF VOLTAGE AT A FIRST INPUT AND PULSES OF VOLTAGE APPLIED TO A SECOND INPUT, COMPRISING A FIRST CAPACITOR CONNECTED BETWEEN THE FIRST INPUT AND THE CONTROL TERMINAL OF A FIRST CURRENT-CONTROLLING DEVICE HAVING, IN ADDITION TO THE SAID CONTROL TERMINAL, AT LEAST A SECOND AND A THIRD TERMINAL, AND CONTROLLING DEVICE BEING SUCH THAT WHEN A SOURCE OF DIRECT VOLTAGE IS APPLIED BETWEEN ITS SECOND AND THIRD TERMINALS IN APPROPRIATE POLARITY CURRENT FLOWS BETWEEN THEM IF THE POTENTIAL OF THE CONTROL TERMINAL IS WITHIN A FIRST RANGE OF VALUES WHILE CURRENT FLOW IS EFFECTIVELY PREVENTED IF THE POTENTIAL OF THE CONTROL TERMINAL IS WITHIN A SECOND RANGE OF VALUES, THE CURRENT FLOW THRU THE CONTROL TERMINAL BEING OF LOW VALUE IN RELATION TO THE CONTROLLED CURRENT, A FIRST RESISTOR FOR ESTABLISHING A TIME CONSTANT WITH SAID FIRST CAPACITOR AND CONNECTED ACROSS SAID CAPACITOR, A FIRST RECTIFIER HAVING TWO TERMINALS THE FIRST OF WHICH BEING CONNECTED TO SAID CONTROL TERMINAL AND BEING OF SUCH POLARITY THAT THE RECTIFIER CONDUCTS CURRENT READILY IN THE DIRECTION REQUIRED TO CHANGE THE POTENTIAL OF SAID CONTROL TERMINAL FROM THE FIRST TO THE SECOND SAID RANGE OF VALUES, A SECOND CAPACTOR CONNECTED BETWEEN THE SECOND TERMINAL OF SAID FIRST RECTIFIER AND SAID FIRST INPUT, A SECOND RECTIFIER WHOSE FIRST TERMINAL IS CONNECTED TO THE SECOND TERMINAL OF SAID FIRST RECTIFIER SAID FIRST TERMINAL BEING OF THE SAME POLARITY AS THE FIRST TERMINAL OF SAID FIRST RECTIFIER, AND WHOSE SECOND TERMINAL IS CONNECTED TO THE COMMON RETURN SIDE OF BOTH INPUTS, THIRD RECTIFIER HAVING THE SAME POLARITY AS THE FIRST RECTIFIER AND WHOSE FIRST TERMINAL IS CONNECTED TO THE FIRST TERMINAL OF THE FIRST RECTIFIER AND WHOSE SECOND TERMINAL IS CONNECTED TO THE SAID SECOND INPUT, A FIRST SOURCE OF DIRECT VOLTAGE CONNECTED BETWEEN THE SECOND TERMINAL OF SAID FIRST CURRENT CONTROL DEVICE AND THE COMMON RETURN SIDE OF BOTH INPUTS AND HAVING A POLARITY CORRESPONDING TO THE POLARITY OF THE CURRENT CONTROL DEVICE, A SECOND RESISTOR CONNECTED BETWEEN SAID FIRST INPUT AND THE CONTROL TERMINAL OF A SECOND CURRENT-CONTROLLING DEVICE HAVING ALSO AT LEAST A SECOND AND THIRD TERMINAL SAID SECOND CONTROLLING DEVICE HAVING THE PROPERTIES THAT WHEN A SOURCE OF DIRECT VOLTAGE IS APPLIED BETWEEN ITS SECOND AND THIRD TERMINALS IN APPROPRIATE POLARITY CURRENT FLOWS BETWEEN THEM IF THE POTENTIAL OF THE CONTROL TERMINAL IS WITHIN A THIRD RANGE OF VALUES WHILE CURRENT FLOW IS EFFECTIVELY PREVENTED IF THE POTENTIAL OF THE CONTROL TERMINAL IS WITHIN A FOURTH RANGE OF VALUES, THE CURRENT THRU THE CONTROL TERMINAL BEING LOW IN RELATION TO THE CONTROLLED CURRENT, A THIRD RESISTOR CONNECTED BETWEEN THE THIRD TERMINAL OF THE FIRST CURRENT-CONTROLLING DEVICE AND THE CONTROL TERMINAL OF THE SECOND CURRENT-CONTROLLING DEVICE, A FOURTH RESISTOR CONNECTED BETWEEN SAID CONTROL TERMINAL OF THE SECOND CONTROLLING DEVICE AND A SOURCE OF OSCILLLATING VOLTAGE WHICH VARIES CYCLICALLY BETWEEN A LARGE AND A SMALL VOLTAGE THE POLARITY OF SAID LARGE VOLTAGE BEING SUCH AS WOULD IF ACTING ALONE CAUSE CURRENT TO FLOW READILY THRU THE SECOND CONTROL DEVICE A CONNECTION BETWEEN SAID SIGNAL DEVICE AND THE SECOND TERMINAL OF SAID SECOND CONTROL DEVICE, A SECOND SOURCE OF DIRECT VOLTAGE CONNECTED BETWEEN SAID SIGNAL DEVICE AND THE COMMON RETURN SIDE OF THE FIRST AND SECOND INPUTS AND HAVING A POLARITY CORRESPONDING TO THE POLARITY OF THE SECOND CONTROL DEVICE, A CONNECTION BETWEEN THE THIRD TERMINAL OF SAID SECOND CONTROL DEVICE AND THE COMMON RETURN OF THE FIRST AND SECOND INPUTS, THE VOLTAGE PROVIDED BY SAID SOURCE OF OSCILLATING VOLTAGE AND BY THE SAID FIRST AND SECOND SOURCES OF DIRECT VOLTAGE AND THE VALUES OF SAID SECOND, THIRD AND FOURTH RESISTORS BEING SUCH THAT: FIRST, WHEN A VOLTAGE HAVING A SUFFICIENT MAGNITUDE AND THE POLARITY OF THE SAID FIRST RANGE OF VALUES IS APPLIED TO THE FIRST INPUT, THE POTENTIAL OF THE CONTROL TERMINAL OF SAID SECOND CURRENT-CONTROLLED DEVICE WILL BE WITHIN THE SAID FOURTH RANGE OF VALUES FOR ALL VALUES OF VOLTAGE RECEIVED FROM SAID SOURCE OF OSCILLATING VOLTAGE AND ESSENTIALLY NO CURRENT WILL FLOW THRU THE SIGNAL DEVICE; AND, SECOND, WHEN WITH NO POTENTIAL APPLIED TO EITHER INPUT THE ELECTRIC CHARGE OF THE SAID FIRST CAPACITOR IS SUCH AS TO APPLY A POTENTIAL TO THE CONTROL TERMINAL OF THE SAID FIRST CURRENT-CONTROL DEVICE THAT IS WITHIN THE SAID SECOND RANGE OF VALUES, ESSENTIALLY NO CURRENT WILL FLOW THROUGH SAID THIRD RESISTOR AND THE POTENTIAL OF THE CONTROL TERMINAL OF THE SECOND CURRENT-CONTROL DEVICE WILL BE CONTINUOUSLY WITHIN THE THIRD RANGE OF VALUES AND CURRENT WILL FLOW CONTINUOUSLY TO THE SIGNAL DEVICE; AND, THIRD, WHEN THE CAPACITORS ARE SUFFICIENTLY DISCHARGED THAT THE POTENTIAL OF THE CONTROL TERMINAL OF THE FIRST CONTROL DEVICE IS WITHIN THE FIRST RANGE OF VALUES, CURRENT FLOWS AND THE POTENTIAL OF THE CONTROL TERMINAL OF THE SECOND CONTROL DEVICE IS MAINTAINED WITHIN THE THIRD RANGE OF VALUES AT MOMENTS WHEN THE SOURCE OF OSCILLATING VOLTAGE IS SUPPLYING LARGE VALUES OF VOLTAGE AND WITHIN THE FOURTH RANGE OF VALUES WHEN THE OSCILLATING VOLTAGE IS IN THE SMALL VOLTAGE PHASE, CURRENT THRU THE SIGNAL DEVICE THEN BEING ALTERNATELY CAUSED TO FLOW AND CUT OFF. 